Currently, lock-out features for control levers operable for controlling critical functions of machines utilized in such industrial fields as agriculture, construction and excavating, mining, forestry, and the like, include external mechanisms, hydraulic circuitry, and/or internal mechanisms operable using a separate lever or other actuating member.
Reference Campbell U.S. Pat. No. 3,795,152 issued Mar. 5, 1974 to Caterpillar Tractor Co.; Kelly et al U.S. Defensive Publication No. T973,003 issued Aug. 1, 1978 to Caterpillar Tractor Co.; and Friesen et al U.S. Pat. No. 4,220,050 issued Sep. 2, 1980 to Towmotor Corporation.
However, the known external lock-out mechanisms suffer from ergometrical shortcomings and are generally aesthetically undesirable for use in modern machines. Known hydraulic lock-out systems have the shortcoming that they do not provide tactile feedback of the locked-out condition. And, separate lock-out levers or other actuators require the operator to remove his or her hand from the lever being locked-out and visual identification of the lock-out lever or other actuator when performing the lock-out function.
Another shortcoming of a wide variety of known lock-out mechanisms is that they have failure modes that can go undetected and result in the control lever being in an unknown operating condition. Still another shortcoming of various known lock-out mechanisms is a lack of adaptability for use with control levers having curved shapes.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.